Styjun

I want to delete all items in ListView1 except youngest student in each group by comparing their date of births.

So, I tried to create a structured database and binding it to my ListView1 but failed with errors & exceptions.

Any help is greatly appreciated.

This is my code-

// assume 'Students is a List<Student>
IEnumerable<Student> earlydatestudents = Students.GroupBy(std => std.Group)
 .Select(grp =>
 
 DateTime dt = grp.Min(s => s.DOB);
 return grp.Where(st => st.DOB == dt);
 )
 .SelectMany(slist => slist);

var toDeleteList = Students.Except(earlydatestudents).ToList();

// 

My ListView1 contains-

Student , DOB , Location

Group1
AAA 10-05-2000 Mumbai
BBB 05-02-2000 Pune
CCC 01-01-2000 Delhi

Group2
DDD 20-03-1999 Lucknow
EEE 15-06-1999 Chennai
FFF 18-09-1999 Ahmedabad

Try following :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Globalization;

namespace ConsoleApplication106

 class Program
 
 static void Main(string[] args)
 
 List<Student> students = new List<Student>() 
 new Student() name = "AAA", dob = DateTime.ParseExact("10-05-2000", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Mumbai",
 new Student() name = "BBB", dob = DateTime.ParseExact("05-02-2000", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Pune",
 new Student() name = "CCC", dob = DateTime.ParseExact("01-01-2000", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Delhi",
 new Student() name = "DDD", dob = DateTime.ParseExact("20-03-1999", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Lucknow",
 new Student() name = "EEE", dob = DateTime.ParseExact("15-06-1999", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Chennai",
 new Student() name = "FFF", dob = DateTime.ParseExact("18-09-1999", "dd-MM-yyyy", CultureInfo.InvariantCulture), location = "Ahmedabad"
 ;


 var results = students.OrderByDescending(x => x.dob) //sort from youngest to oldest
 .GroupBy(x => x.dob.Year) //group by year
 .Select(x => x.First()) //get first student born each year which is youngest
 .ToList();
 

 
 public class Student
 
 public DateTime dob get; set; 
 public string name get; set; 
 public string location get; set;